Iron-treated NiO as a highly transparent p-type protection layer for efficient Si-based photoanodes

Bastian Mei, Anastasia A. Permyakova, Rasmus Frydendal, Dowon Bae, Thomas Pedersen, Paolo Malacrida, Ole Hansen, Ifan E. L. Stephens, Peter C. K. Vesborg, Brian Seger, Ib Chorkendorff

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86 Citations (SciVal)


Sputter deposition of 50 nm thick NiO films on p+-n-Si and subsequent treatment in an Fe-containing electrolyte yielded highly transparent photoanodes capable of water oxidation (OER) in alkaline media (1 M KOH) with high efficiency and stability. The Fe treatment of NiO thin films enabled Si-based photoanode assemblies to obtain a current density of 10 mA/cm2 (requirement for >10% efficient devices) at 1.15 V versus RHE (reversible hydrogen electrode) under red-light (38.6 mW/cm2) irradiation. Thus, the photoanodes were harvesting ∼80 mV of free energy (voltage), which places them among the best-performing Si-based photoanodes in alkaline media. The stability was proven by chronoamperometry at 1.3 V versus RHE for 300 h. Furthermore, measurements with electrochemical quartz crystal microbalances coupled with ICP-MS showed minor corrosion under dark operation. Extrapolation of the corrosion rate showed stability for more than 2000 days of continuous operation. Therefore, protection by Fe-treated NiO films is a promising strategy to achieve highly efficient and stable photoanodes.

Original languageEnglish
Pages (from-to)3456-3461
Number of pages6
JournalJournal of Physical Chemistry Letters
Issue number20
Publication statusPublished - 16 Oct 2014


  • electrochemical quartz crystal microbalance
  • oxygen evolution reaction (OER)
  • photoelectrochemical water splitting
  • stability
  • thin film

ASJC Scopus subject areas

  • Materials Science(all)
  • Physical and Theoretical Chemistry


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